Form for casting concrete structural units

ABSTRACT

A form for casting structural units of the type involving at least a concrete slab and side beams and may include end beams and corner legs, the form including beam casting forms slidable a limited distance on an underlying surface between a casting position and a clearance position, each beam casting form being itself a concrete structure secured to the underlying structure by steel straps the extremities of which are anchored in the beam casting form and the underlying structure, whereas the central portions are encased in an elastomer to permit limited movement of the beam casting form.

United States Patent Edward K. Rice [72] Inventor 2077 Linda FloraDrive. Los Angeles, Calif. 90024 [21] Appl. No. 829,224 122] Filed June2,1969 {45] Patented July 27, 1971 l 54] FORM FOR CASTING CONCRETESTRUCTURAL UNITS 4 Claims, 6 Drawing Figs.

[52] 0.8. CI .1 249/155, 25/121.249 50, 18/34 R (51] Int. Cl B28b 7/02[50] Field otSearch 249/155,

158, 160, 161, 162,50; 25/121, 1 18 Q, 118T; 18/34 R, 42 R, 5 R; 52/425,743, 744

[56 1 References Cited UNITED STATES PATENTS 2,394,227 2/1946Barber....,......... 25/1 18 (T) 2,425,610 8/1947 Finley .5 249/115 X2,556,928 6/1951 Lud1ow 25/118 (T) 3,475,529 10/1969 Lacy 25/1 18 (T) XPrimary Examiner-J. Spencer Overholser Assistant ExaminerDewalden W.Jones Att0rney-Ly0n and Lyon ABSTRACT: A form for casting structuralunits of the type involving at least a concrete slab and side beams andmay in-- clude end beams and comer legs, the form including beam castingforms slidable a limited distance on an underlying surface between acasting position and a clearance position, each beam casting form beingitself a concrete structure secured to the underlying structure by steelstraps the extremities of which are anchored in the beam casting formand the underlying structure, whereas the central portions are encasedin an elastomer to permit limited movement of the beam casting form.

FORM FOR CASTING CONCRETE STRUCTURAL UNITS BACKGROUND OF THE INVENTIONThe present invention pertains to forms for repeated casting of concretestructural units; for example, concrete slabs having side beams andpossibly end beams as well as corner legs. Such structural units beingdisclosed in my copending application, Ser. No. 837,986, filed June 2,I969, entitled Precast Concrete Building Construction. Such structuralunits preferably utilize expansive concrete which on setting and curingundergoes expansion. The expansion may be sufficient to place internalreinforcing under tension to hold the concrete under compression, or maybe merely enough to compensate for shrinkage. Expansive concretesuitable for the purposes of this invention are disclosed in U.S. Pat.No. 3,215,701 and No. 3,303,037.

SUMMARY OF THE INVENTION The objects of the invention are summarized asfollows:

First, to provide a form for casting concrete structural units which isintended to be used repeatedly and wherein a series of forms may bearranged in tandem and provided with tracks so that appropriate vehiclescarrying mixers or premixed concrete, finishing machines and the likemay be moved along the tracks to service the forms.

Second, to provide a form particularly suited for, but not limited to,the casting of concrete slabs including marginal beams as well as comerlegs and which may utilize expansive concrete.

Third, to provide a form which incorporates unique beam casting membersconstructed of concrete, to provide rigidity, and capable of limitedmovement to permit moving the form member clear of the beam cast therebyto permit removal of the structural unit.

DESCRIPTION OF THE DRAWINGS FIG. I is a fragmentary plan view of theform for casting concrete structural units.

FIG. 2 is an enlarged fragmentary transverse sectional view, takenthrough 2-2 of FIG. 1.

FIG. 3 is another fragmentary transverse sectional view thereof, takenthrough 3-3 of FIG. 1.

FIG. 4 is an enlarged fragmentary sectional view, taken within Circle 4of FIG. 2.

FIG. 5 is an enlarged fragmentary sectional view, taken through 5-5 ofFIG. 3.

FIG. 6 is an enlarged fragmentary sectional view, taken within Circle 6of FIG. 2, showing a portion of a concrete member cast by the form andcasting rod therein.

The form for casting concrete structural units includes a slab castingform 1, which is shown as a raised rectangular body of concrete,provided with essentially vertical sidewalls 2. Supporting pads 3 alsoformed of concrete extend laterally from the base of each sidewall 2.Resting on each supporting pad is a side beam casting form 4. Eachcasting form 4 is constructed of concrete of relatively massive crosssection and extends the length of the slab casting form 1. The lowercorners of the casting form 4 are provided with reinforcing strips 5 and6 of metal.

Interposed between each form 4 and the pad 3 is an antifriction membrane7; for example, a polyethylene sheet may serve this purpose; or certainof the halogen substituted polyethylene compositions may serve thispurpose.

At spaced intervals, each casting form 4 and the underlying pad 3 arejoined by a tie strap 8. It has been found that an automobile leafspring is satisfactory for this purpose. The extremities of the tiestraps are bonded directly to the concrete and may be welded to internalreinforcing 9 and I0 embedded in the form 4 and pad 3, respectively.

The midportion of each tie strap is encased in a body 11 of elastomericmateriahsuch as rubber or synthetic rubber, or

the more yieldable plastic materials. In practice, each supporting pad 3is east in place with the tie straps 8 and the upper portions of theelastomeric bodies 11 projecting upwardly therefrom. Later, the forms 4are cast in place utilizing the membranes 7 to prevent adherence to theunderlying pad 3.

Cast in each form 4 near the bottom thereof is a set of horizontallyextending adjustment bolts 12, which project outwardly from the form 4and through upstanding portions of corresponding anchor brackets 13. Thebolts 12 receive adjustment nuts 14 so that the casting form may bemoved to and from the corresponding sidewalls 2 within the limitspermitted by the elastomeric bodies I l.

The upper side of each casting form 4 is provided with an angle bracket15 which constitutes a form for casting the edge of the slab cast by theform 1. Partially embedded in the upper side of each casting form 4 is atrack 16 which is used to guide various toolsor vehicles, such asconcrete mixers, containers for the mixed concrete to be poured over theforms, as well as leveling devices or finishing machines for theconcrete slab cast on the form I.

' If the concrete casting form is to be employed for the casting ofstructural units having legs in the corners thereof, as shown in theaforementioned copending application, a pit 17, deep enough to cast suchlegs, is provided at each end of the slab casting form 1. Each pitincludes a wall 18, the upper portion of which may be recessedapproximately the depth of the sidewalls 2 so as to form end beamcasting walls 19. In alignment with the side beams to be cast betweenthe sidewalls 2 and the forms 4 are vertical leg casting channels 20.The bottom of each pit is provided with suitable guide tracks 21, onwhich are mounted end casting forms 22 which abut the wall 18 and closethe channels 20 to provide the cavity for casting the legs of thestructural unit. Also, the end form 22 cooperates with the end beamcasting walls. 19.

Operation of the structural unit casting form is as follows:

Appropriate reinforcing, not shown, is placed in the cavities of theform and over the slab casting form 1. Such reinforcing may includetendons placed in the space between the sidewalls 2 and the side beamcasting forms 4. The sidewalls of the various cavities, including thechannels 20, are appropriately tapered to permit the cast structure tobe removed from the forms. After the concrete has been poured, andundergone an initial set, the side beam casting forms 4 are moved awayfrom the sidewalls 2. The amount of such movement depends upon theultimate expansion of the concrete and a sufficient additional distanceto separate the casting form 4 from the beams. Similarly, the endcasting forms 22 are moved away from the ends of the slab casting formso as to free the legs cast in the channels 20. In the course of castingthe structural unit, appropriate lifting members have been cast therein,preferably at the corners thereof, so that the structural unit may belifted from the form.

In practice, a series of the casting forms shown in FIG. 1 are arrangedin end-to-end relation with an end pit between each pair of forms, andtracks 23, alongside each pit, link the tracks 16, and the tracks 16align therewith when the casting forms 4 are in the proper position forcasting the side beams of the structural unit.

Reference is directed to FIG. 6. It is essential in the casting ofbuilding units such as disclosed in the copending application, Ser. No.837,986, that passages to receive transverse tendons be cast in the slabportion of the building unit. This is accomplished by use of castingbars 24, preferably formed of metal of suitable cross section and coatedwith a suitable parting agent. The ends of each bar are supported inopenings provided in the edge casting flanges 15. It has been found thatduring the curing period of the concrete, there is a period in which theconcrete is self-sustaining yet has not set sufficiently that thecasting bars cannot be withdrawn. This condition is improved if someexpansive cement is used.

While particular embodiments of this invention have been shown anddescribed, it is not intended to limit the same to the details of theconstructions set forth, but instead, the invention embraces suchchanges, modifications and equivalents of the various parts and theirrelationships as come within the purview of the appended claims.

I claim:

A form for casting structural units having a slab and side beams, saidform comprising:

a slab casting form including beam casting sidewalls;

b. supporting pads extending laterally outward from the botanelastomeric body encasing the central portion of each tie member andembedded in the confronting portions of each pad and correspondingcasting member;

. and means for moving each casting member to and from the correspondingcasting sidewall within the limits permitted by said elastomeric bodies.

2. A form, as defined in claim 1, wherein:

a friction reducing plastic membrane is interposed between each castingmember and corresponding pad. A form, as defined in claim 1, wherein:

a pit is located at each end of said slab casting form and includes awall having leg casting channels therein aligning with the beam castingspace between said beam casting sidewalls and casting members;

and an end form movable in each pit between a casting position closingsaid channels and a releasing position.

A form for casting structural units, comprising:

a fixed wall casting form;

a supporting pad extending laterally from the bottom of said fixed form;

a movable wall casting form confronting said fixed form and mounted onsaid pad; said movable form being movable between a casting positionwith respect to said fixed form and a releasing position for removal ofa wall member cast between said forms;

. a plurality of tie members having ends embedded in said movable formand said supporting pad;

an elastomeric body encasingthe central portion of each tie member andembedded in the confronting surfaces of said movable form and said pad;

and means for moving said movable member with respect to said pad withinthe limits permitted by said elastomeric bodies.

1. A form for casting structural units having a slab and side beams,said form comprising: a. a slab casting form including beam castingsidewalls; b. supporting pads extending laterally outward from thebottom margins of said sidewalls; c. a massive beam and slab edgecasting member slidable on each pad to and from each beam castingsidewall between a beam casting position and a beam releasing position;d. a plurality of yieldable tie members, each having an upper endembedded in a casting member and a lower end embedded in the pad below;e. an elastomeric body encasing the central portion of each tie memberand embedded in the confronting portions of each pad and correspondingcasting member; f. and means for moving each casting member to and fromthe corresponding casting sidewall within the limits permitted by saidelastomeric bodies.
 2. A form, as defined in claim 1, wherein: a. afriction reducing plastic membrane is interposed between each castingmember and corresponding pad.
 3. A form, as defined in claim 1, wherein:a. a pit is located at each end of said slab casting form and includes awall having leg casting channels therein aligning with the beam castingspace between said beam casting sidewalls and casting members; b. and anend form movable in each pit between a casting position closing saidchannels and a releasing position.
 4. A form for casting structuralunits, comprising: a. a fixed wall casting form; b. a supporting padextending laterally from the bottom of said fixed form; c. a movablewall casting form confronting said fixed form and mounted on said pad;said movable form being movable between a casting position with respectto said fixed form and a releasing position for removal of a wall membercast between said forms; d. a plurality of tie members having endsembedded in said movable form and said supporting pad; e. an elastomericbody encasing the central portion of each tie member and embedded in theconfronting surfaces of said movable form and said pad; f. and means formoving said movable member with respect to said pad within the limitspermitted by said elastomeric bodies.